Carmine Senatore , Marco Bonura, Christian Barth, Damien Zurmuehle - PowerPoint Presentation

Slide1

Carmine

Senatore, Marco Bonura, Christian Barth, Damien Zurmuehle

Department of Quantum Matter Physics, University of Geneva, Switzerland

Progress, plans and comparisons

of

HTS materials and SC cables

Slide2

High Temperature Superconductors and (Ultra-)High Field Superconductors

Superconductors and Future accelerators

What we need from superconductors

Outline

Where we are going

An overview of the possibilities and of the challenges

Slide3

Temperature

Magnetic field

77 K

4.2 K

30 K

60 K

32 T

10 T

5 T

Temperatures and magnetic fields accessible for applications with the superconductors of today

Slide4

Temperature

Magnetic field

77 K

4.2 K

30 K

60 K

32 T

10 T

5 T

Temperatures and magnetic fields accessible for applications with the superconductors of today

LTS

Nb-Ti

Nb

3

Sn

LTS Nb

3

Sn ultimate limits are

23.5 T in

solenoids @ 2.2 K

achieved

16

T in

dipoles @ 1.9 K

targeted

HTS

HTS

for magnet applications are

ultra-high field superconductors

16 T

23.5 T

45.5 T generated with a YBCO-based insert at

MagLab

Hahn et

al

., Nature

570

(2019)

496-499

Slide5

High current density at high fields

High tolerance to stress

Be safe in case of magnet quenchHave low magnetizationField quality requires multifilamentary wires with fine filaments

Superconductors R&D for HEP

What do we need ?

Stress increases proportionally to field, current density and magnet size.

FCC 16 T dipoles

are being designed with

a

peak stress

in the range of

150-200 MPa

at

operation

Stability increases with Top – Tc

but quench detection becomes

tricky

Slide6

Superconductors R&D for HEP

Build on the experience and explore the

ultimate performance of Nb3Sn towards 16 T

conductor development program

Where do we go ?

Two main directions

Drive the

HTS

technology development towards

20+T accelerator magnets

EU projects

Slide7

Nb

3Sn, the benchmark

Nb3Sn

Discovered in 1954

T

c

= 18 K Bc2(T = 4.2 K) = 28 T

Performance target for the 16 T FCC dipoles

non-Cu

J

c

(4.2 K,16 T)

= 1’500

A/mm

2

Slide8

YBa

2

Cu3O7-x(RE)Ba2

Cu

3

O

7-xBi2Sr2CaCu2O8+x

Ba

1-x

K

x

Fe

2

As

2

Discovered in 1987Discovered in 1988

Discovered in 2007

T

c

= 92 K Tc = 89 KTc = 38 KBc2(T = 4.2 K) > 100 TUltra-high field (UHF) SuperconductorsBeyond the limits of Nb3SnHigh Temperature SuperconductorsIron-Based Superconductors (IBS)

Slide9

YBa

2Cu

3O7-x (YBCO) coated conductors

Ag cap layer

Cu stabilisation

Y

BCO layer

metallic substrate

buffer layers

~1 µm of YBCO in

a ~

100 µm thick tape

[001]

tilt grain boundary

H.

Hilgenkamp

and

J.

Mannhart, RMP 74 (2002) 485

Slide10

Ag cap layer

Cu stabilisation

YBCO layermetallic substrate

buffer layers

Biaxial texturing – within 3° to 5° – is obtained

a

b

a

b

a

b

a

b

a

a

b

a

b

Top view

The template is a metallic substrate coated with a multifunctional oxide barrier Presently produced by

complex and expensive production route

pronounced anisotropic behaviour

but with some also drawbacks:

YBa2Cu3

O7-x (YBCO) coated conductors~1 µm of YBCO in a ~100 µm thick tape

Slide11

Progress in YBCO coated conductor performance

YBCO 3.8

m / SS 100 m(2013)

YBCO layer

How to

increase the critical current ?

Increase the layer

J

c

of YBCO

Increase the thickness of YBCO

Reduce the thickness of the substrate

Tapes

manufactured by , industrial partner in the EU projects

20 T

400 A/mm

2

600 A/mm22013 – 2017 YBCO 2.0 m / SS 100 m 20 T 800 A/mm21200 A/mm22017 – 2021 YBCO 2.0 m / SS 50 m

Slide12

Progress in performance from other manufacturers

Similar

J

c

of the REBCO layer

Differences come from the conductor architecture

2’000 A/mm

2

@ 4.2K, 19T

1’000 A/mm

2

@ 20K, 19T

Operation in high field possible even above

LHe

temperature

Nb

3

Sn

Slide13

From YBCO tapes to YBCO cables

YBCO tapes have current capability of ~1000 A

Dipoles and quadrupoles require large operating currents ~ 10 kA, to keep the inductance low and to ease magnet protection

Roebel

Cable

Twisted Staked-Tape Cable (TSTC) Conductor on Round Core Cable (CORC)

There are three cable options

Slide14

From YBCO tapes to YBCO cables

YBCO tapes have current capability of ~1000 A

Dipoles and quadrupoles require large operating currents ~ 10 kA, to keep the inductance low and to ease magnet protection

There are three cable options

Roebel

TSTC

CORC

Production

Lab/Industry

Lab

Industry

J

e

@ 4.2 K, 20 T

> 600 A/mm

2

(



)

200 A/mm2~400 A/mm2In-field Anisotropy~51, Isotropic1, IsotropicTranspositionFullPartialPartialStress tolerance(transverse load)> 400 MPa(impregnated)~50 MPa~300 MPaBending radius10 mm(easy bend)>100 mm50 – 100 mm

Slide15

Progress in Bi2212 performance

Round

multifilamentary Bi2212 wires can be assembled in Rutherford cables

Reaction @ 1 bar in O

2

Reaction @ 100 bar

Larbalestier

et al

., Nat. Mat.

13

(2014) 375

50% increase of J

e

by removing the bubbles in the filaments with high pressure

Improved precursors

+ reaction @ 50 bar

Further enhanced J

e

up to 1’400 A/mm2 at 15 T with better precursorsJiang et al. @ MT25 (2017)is the only industrial manufacturer

Slide16

Electromechanical properties of Bi2212 wires

Shen et al., Sci. Reports

9 (2019) 10170

2-layer, 6-turn racetrack using 8 m of

17-wire

Rutherford cable

Coils reacted at 50 bar in partial O2 pressure Ceramic Bi2212 filaments are embedded in a soft Ag matrixThe reduction of critical current under load is irreversible

Solutions for the mechanical reinforcement are needed

Barth

et al

. @ ASC2016

Slide17

Progress in IBS performance

Ba

1-xKxFe2As

2

Great improvement since 2012

Monel

Silver

Adapted from Ma et al. @ EUCAS 2019

in the superconductor

in the whole conductor

1’500 A/mm

2

Slide18

Peculiar properties of IBS tapes

Wire technology still in its infancy

Magnetic hysteresis = granularity, weak linksAnomalous increase of the critical current at low fields = magnetic impurities

Adapted from Bonura et al. @ EUCAS 2019

Best performance achieved in densified tapes (hot rolling, hot pressing, etc.)

Slide19

Nb

3SnYBCO

Bi2212IBSJe(4.2K, 20T)

200 A/mm

2

2’000 A/mm

21’200 A/mm2270 A/mm2Je(20K, 20T)

–

1’000 A/mm2

150 A/mm

2

55 A/mm

2

In-field Anisotropy1, Isotropic~51, Isotropic

~2

Stress tolerance

(Transverse load)

~150 MPa> 400 MPa70 MPa – Quench protectionAchievedComplex work in progressPossible – MultifilamentaryYes(finer filaments would be better)NoYesYes(still low count)ChallengesWind & React R&D needed to reach ultimate performanceReduce the costDevelop long lengths Cable technologyMagnetizationWind & reactComplex reaction at 50 barMechanical propertiesStill a laboratory materialProgress needed towards practical conductors Comparison at a glance

Slide20

To conclude…

In particular, high performance

YBCO coated conductors are available from several ( > 5) industrial manufacturers Different concepts of high current cables are being developed at laboratory and industrial level but the perfect solution is not yet there

Still there are concerns

– conductor

available lengths and

cost, quench propagation and protection, field qualityHigh performance technical conductors based on HTS are on the market and pave the way

to disruptive high-field magnet

technology (and to higher efficiency with operation at T > 1.9 K)

Need to work more on demonstrators to foster the development!

Slide21

Thank you for the attention !

Carmine SENATORE

carmine.senatore@unige.ch

http://supra.unige.ch

Slide22

Slide23

Operation in high field possible even above

LHe temperature

High current density at high field even at T > 4.2 K

Slide24

I

c

T

I

c

T

c

T

op

I

op

0

T

cs

Stability and quench protection

T

op

REBCO tapes are intrinsically stable

The temperature margin

Top at 4.2 K, 20 T is large ~30 K The stability margin is also very large ~1 J/cm32 to 3 order of magnitude larger wrt Nb3SnThe reverse of the medal is that REBCO-based magnet are difficult to protect against quenchesOnce a thermal disturbance creates a hot spot, it propagates slowly and is therefore hard to detect

Slide25

magnetic lines of force

vectors of electromagnetic force per unit volume

Conductors in the winding are exposed to 3D stresses that combine axial tension and transverse compression

Electromagnetic forces in a magnet

Stress increases proportionally to field, current density and magnet size

Slide26

IBS: conductor technology

100

meter-class iron-based superconducting wire has been demonstrated7-filament Ag-sheathed PIT Sr122 tape

Minimum

I

c

 100 A

Zhang et al., IEEE TAS

27

(2017) 7300705